1. Field of the Invention
The present invention relates to a method of producing a blade for an electrophotographic apparatus used in an electrophotographic apparatus and to a blade for an electrophotographic apparatus.
2. Description of the Related Art
In general, an electrophotographic apparatus is structured such that a toner image on a photosensitive drum is transferred to a recording sheet, the toner remaining on the photosensitive drum is removed, and then transfer is repeatedly performed using the photosensitive drum. Therefore, the electrophotographic apparatus is provided inside with a cleaning blade in which a blade member is joined to a support, a developing blade which forms a thin layer while triboelectrically charging a toner in a developing assembly, etc.
In the cleaning blade, a holder formed of metal for attaching the blade to the electrophotographic apparatus or the like and the blade member which is formed of an elastic material and attached to one side of the holder are integrally formed. As a material forming the blade member, a thermosetting polyurethane elastomer is usually used because the degree of each of the wear resistance and the permanent deformation or the like is excellent.
However, when a conventional blade formed of a thermosetting polyurethane elastomer is used, the friction coefficient between the blade member and the photosensitive drum has increased in some cases. As a result, the blade is turned up; an abnormal noise is generated; and the driving torque of the photosensitive drum is required to be increased. Moreover, in recent years, since the processing speed increases, such problems tend to more remarkably occur.
Thus, various methods have been attempted so as to prevent the blade from turning up due to friction between the blade and the photosensitive drum.
(1) As the first method, a method is given involving coating the surface of the blade with lubricant powder.
(2) As the second method, a method is employed involving increasing the hardness throughout a thermosetting polyurethane elastomer which is a blade material to thereby reduce the friction.
(3) As the third method, a method is given involving reducing the friction of only the surface of the blade member formed of a thermosetting polyurethane elastomer to thereby maintain the elasticity throughout the blade. Specifically, according to this method, the blade member is coated with polysilazane to thereby reduce the friction of only the surface of the blade member (see, for example, Japanese Patent Application Laid-Open No. H08-314343).
In contrast, as a different problem from the above, when a cleaning blade formed of a polyurethane elastomer is used, the contact part has been chipped off in some cases because the blade is repeatedly rubbed with the photosensitive drum. In this case, a problem arises in that toner escapes from the chipped part, resulting in poor cleaning. Thus, in order to improve the wear resistance, it has been proposed that the crosslinking density in a polyurethane elastomer is adjusted to 8.5 ×10−4 to 11.0 ×10−4 mol/cm3 (see, for example, Japanese Patent Application Laid-Open No. H11-212418).